It is to be noted that while the following description for the most part uses the example of the supply of energy to the thermal storage apparatus, as being solar based, the scope of the invention should not be considered so limited.
The solution provided for by this invention would equally work as well if other heating or electrical elements are used to supply energy to the thermal storage apparatus, which is then able to convert thermal energy created and stored in the apparatus to electrical and/or mechanical energy as required.
For example wind turbines and so forth could be used just as well as an interrupted solar supply of energy to the thermal storage apparatus that is adapted to continuously convert the thermal energy to electrical and/or mechanical energy.
As most members of the purchasing public are aware, there has been a push in recent years to move away from fossil fuels as a means of deriving various energy sources. The move towards what is generally characterised as cleaner fuel sources has seen significant development in the field of the use of solar as a means of providing usable forms of energy.
Nonetheless, by its very nature, solar's biggest pitfall is the fact that, at certain times of the day the inability for the sun to provide the necessary photons of energy or heat to various apparatus that utilise this source of energy, means that they remain inoperative.
Interrupted or inconsistent supply of energy from a source makes it, in many instances, unreliable and also uneconomical.
Still further, in certain instances, the sun's rays are so excessive that this useful heat and energy, which it is providing to the apparatus that is converting such energy to more workable forms of energy, is simply dissipated as over-supply during such periods.
Therefore, it would be particularly advantageous to be able to bring together an arrangement which could still be involved in utilising the energy derived from the sun through its solar activity, even in times when such solar activity is not available, and still further utilise this, what one could consider, oversupply of solar energy during such periods also.
In Australian Provisional Patent Application No. 2008903800, a thermal energy conversion system was provided that was able to address some of these difficulties.
Through the construction of a thermal energy storage apparatus that included an elemental form of silicon, for the first time it was possible to utilise the unique features of a elemental form of silicon material as a means of storing thermal energy inside the material for use at a later time, for example, when the solar input form the sun was no longer available, such as during the evenings or times of inclement weather.
Basically, as described in Australian Provisional Patent Application No. 2008903800, during peak solar activity the elemental form of silicon material would absorb thermal energy as it transformed its physical state from a solid to a liquid.
Elemental form of silicon material is characterised by the unique property not dissimilar to water and ice, where on solidifying, there is actually an expansion of the material rather than expected contraction thereof.
The initial heat transfer of energy into the elemental form of silicon material from its solidified state to a liquid allows the unique ability of being able to maintain or store thermal energy.
This absorbed thermal energy, which remains stored within the elemental form of silicon material, is then re-introduced back into the apparatus for maintaining the necessary supply of thermal energy, which for the most part, would be converted into either electrical and/or mechanical action through electrical devices such as a Stirling engine and so forth.
Hence, for the first time, this invention described in Provisional Patent Application No. 2008903800, through the use of the elemental form of silicon material, provided a means in which consistent supply of thermal energy could be given to converters of such thermal energy into electrical and/or mechanical energy for their continual operation, despite the fact that the initial source or supply of thermal energy was the result of solar activity.
Nonetheless, the use of elemental form of silicon material is one that requires significant care and understanding of its physical transformation during its expansion and contraction as it absorbs, first of all, thermal energy to move towards a liquid state, store the material, but then at the same time its expansion, as it changes from a liquid state back to the solid.
The expansion and contraction of the elemental form of silicon material creates significant build-up of pressure on the enclosure or confinement in which it is placed inside the energy storage apparatus, which functions as supplying a continual thermal source to electrical devices such as the Stirling engine which utilises the thermo-dynamic principles of the Stirling cycle to convert thermal energy into electrical energy.
The person skilled in the art will immediately appreciate the significant deficiencies in the means in which the elemental form of silicon material is housed inside the thermal energy storage apparatus described in Provisional Patent Application No. 2008903800.
In one embodiment described in the document, it is taught that the elemental form of silicon material would be ingots, which would be introduced into a series of longitudinal cavities that have been shaped into the pressurised moulded block of sintered graphite.
As the person skilled in the art would know such an arrangement would result in the metalloid being absorbed by the graphite when the phase change occurred.
In this embodiment the graphite would also act as an energy absorbing material, which would receive initial thermal energy input from the solar source and then distribute this into the cavities containing the elemental form of silicon ingots.
The elemental form of silicon ingots would then accept this transfer of thermal energy, undergo the change of state, and therefore maintain what could best be described as a storage or latent supply of thermal energy.
While the provisional patent application filed under Patent No. 2008903800 discusses the fact that the cavities contain the elemental form of silicon ingots will allow for thermal expansion, from a practical point of view, the continual pressure build-up and then collapsing of the elemental form of silicon ingots as they move between the respective states of solidifying and liquefying to provide or store the necessary thermal energy transfer, has seen these kinds of cavities and also the supporting moulded sintered graphite about the elemental form of silicon ingots crack and fissure in structure.
Therefore, there clearly remains a need to come up with an improved means in which to house the elemental form of silicon material, so that as it undergoes its various transformation from the respective liquid and solid states, the pressure build-up and so forth does not translate to the cracking and destruction of the overall storage apparatus.
There would also be a need for such a housing of the elemental form of silicon ingots, which would see it more appropriately concentrating, or being able to distribute, the thermal heat to be transferred during the respective state transformation between the elemental form of silicon material and the energy absorbing material that surrounds such elemental form of silicon material within the thermal energy storage apparatus.
A further problem with Provisional Patent Application No. 2008903800 was the fact that the solar reflector arrangement that was responsible for acting as a solar collector so as to provide a concentrated solar energy input into the storage apparatus, has proved to be insufficient in design and performance when tested in simulated conditions.
The current arrangement of the parabolic reflector is such that rather than having a focal point, at best there is a focal region, which sees a dilution or general dissipation of the concentrated solar input to the focal point.
Therefore, there also remains the need, when dealing with energy generation apparatus that includes the use of Stirling engines with solar reflectors, to have a solar collector arrangement able to more appropriately concentrate solar energy onto a focal point.
Accordingly, it is an object of this invention to provide an improved thermal energy storage apparatus arrangement and method over and above those that have hitherto been made available, and in particular the embodiments described and defined in Australian Provisional Patent Application No. 2008903800.
Further objects and advantages of the invention will become apparent with the complete reading of this specification.